Inner flame burner for regeneration of diesel particulate filter

ABSTRACT

Provided is a burner for regenerating a diesel engine particulate filter. The burner includes: a combustion chamber for receiving exhaust gas from a diesel engine; a carburetor for gasifying liquid fuel; a mixed gas supplying unit for mixing the gasified fuel with an external air, and supplying the mixed gaseous fuel to the combustion chamber; a mixed gas storing chamber disposed in the combustion chamber for receiving the mixed gaseous fuel and instantly storing the received mixed gaseous fuel; an inner flame combustor made of porous material for injecting the mixed gaseous fuel toward the inside of the inner flame combustor, and disposed in the combustion chamber to allow an exhaust gas to flow through the inner flame combustor; an igniter for igniting the mixed gaseous fuel; and a flame sensor for sensing the flame on the inner flame combustor.

TECHNICAL FIELD

The present invention relates to a diesel particulate filter (DPF); andmore particularly, to a burner for regenerating a DPF that reduces sootby filtering soot particles included in an exhaust gas outputted from adiesel engine.

BACKGROUND ART

Diesel engines have been generally equipped in trains, vessels, andcommercial vehicles. Also, diesel passenger vehicles came out to themarket, recently. Thus, the use of diesel engines has increased.

As the use for diesel engines has increased, the large amount ofparticulate matters (PM) such as soot and soluble organic fraction (SOF)are produced from the diesel engines. Since such particulate matters(PM) are major factors for environment pollution, especially, airpollution. Therefore, the regulation of diesel engines has becometightened.

In order to resolve the pollution problem of diesel engines, a dieselparticulate filter (DPF) was introduced. The DPF collects soot outputtedfrom a diesel vehicle in order to prevent soot particles from beingexhausted into the air. Also, there are many researches in progress fordeveloping the DPF.

FIG. 1 shows a conventional diesel particulate filter for reducing sootproduced from a diesel engine, which were introduced in Korea PatentPublication No. 2003-0003599.

Referring to FIG. 1, the conventional diesel particulate filter (DPF)includes a main body 10 having a monolith type ceramic filter 11 forfiltering soot particles in an exhaust gas outputted from a dieselengine, and a burner 1 for generating the monolith ceramic filter 11.The burner 1 includes a combustor 4 for injecting mixed fuel suppliedfrom a fuel injection pump 2 and an air pump 3, and an ignition rod 5.

In the conventional DPF, soot particles included in the exhaust gasoutputted from the diesel engine are collected by the monolith typeceramic filter 11. When the large amount of soot particles is trapped inthe ceramic filter 11, the pressure loss of the ceramic filter 14significantly increases. It greatly influences the back pressure of adiesel engine. Therefore, the soot particles collected in the filtermust be removed regularly from the filter 11 when a predeterminedpressure is dropped. Conventionally, the soot particles are removed fromthe filter 11 by increasing the temperature of exhaust gas to be higherthan the oxidation temperature of the soot, for example, higher than600° C., so as to oxidize (burn) the soot particles trapped in theceramic filter 11. In order to raise the temperature of the exhaust gasto be higher than the oxidation temperature of the soot particles, theflame of the burner 1 is used as a heat supplying device. That is, apressure sensor 6 may sense that an internal pressure of the ceramicfilter 11 increases after the large amount of soot particles such ascarbon is trapped in the filter. Then, the pressure sensor 6 informs thecontroller 7 that the internal pressure increases, and the controller 7drives the burner I to burn the soot particles in the filter 11. Then,the combustor 4 injects the fuel, and the ignition rod 5 ignites thefire on the injected fuel. The combustor 4 raises the internaltemperature of the exhaust gas channel 20, while a flame holder 8sustains the flame made by the combustor 4. Therefore, the sootparticles collected at the ceramic filter 11 are burned and eliminated.Then, the ceramic filter 11 can be newly used to collect the sootparticles outputted from the diesel engine.

As described above, the conventional liquid fuel injection type burnerlengthily forms the flame as shown in FIG. 1. It is difficult to stablysustain the lengthily formed flame although the flame holder 8 isincluded. Also, the stability of the flame is greatly influenced bydriving conditions of the engine. That is, it is very difficult tostably sustain when the amount of following the exhaust gas outputtedfrom the engine and the pressure conditions change abruptly. Thus, theflame uncontrollably shakes in the exhaust gas, and is easilyextinguished. These shortcomings make the conventional DPF to becomeunpractical.

Especially, the amount of flowing the exhaust gas or the pressureabruptly varies when the diesel engine accelerates or decelerates. Inthis case, it is very difficult to increase or sustain the temperaturein the exhaust gas channel 20 because the abrupt variation makes theflame instable and to be extinguished. Accordingly, the regeneration ofthe filter through oxidizing the soot particles trapped in the filterbecomes difficult. That is, the conventional burner may sustain theflame stably when the diesel engine is regularly driven, for example,when the engine is kept ticking over, when the engine is driven at aconstant speed, and when the engine stops. However, the conventionalburner cannot sustain the flame stably or often extinguishes the flamewhen the driving conditions of the diesel engine abruptly change, forexample, when the diesel engine accelerates or decelerates. In thiscase, the conventional burner cannot smoothly burn the soot particlestrapped in the filter 11. Therefore, the state of the diesel particulatefilter is getting deteriorated. Finally, the filter 11 becomes incapableof filtering diesel particulate.

DISCLOSURE OF INVENTION Technical Problem

It is, therefore, an object of the present invention to provide a burnerfor generating a diesel particulate filter, which is enhanced toconstantly sustain a stable flame in the flow of exhaust gas withoutbeing influenced by the abrupt variation of driving conditions of thediesel engine.

Technical Solution

In accordance with one aspect of the present invention, there is aburner for regenerating a diesel engine particulate filter including: acombustion chamber for receiving a exhaust gas from a diesel enginethrough at least one of connecting pipes connected to an exhaust gaschannel of the diesel engine; a carburetor for gasifying liquid fuel; amixed gas supplying unit for mixing the gasified fuel from thecarburetor with an external air for burning, and supplying the mixedgaseous fuel to the combustion chamber; a mixed gas storing chamberdisposed in the combustion chamber for receiving the mixed gaseous fuelfrom the mixed gas supplying unit and instantly storing the receivedmixed gaseous fuel; an inner flame combustor made of porous material forinjecting the mixed gaseous fuel supplied from the mixed gas storingchamber in a direction from the outside to the inside of the inner flamecombustor, and disposed in the combustion chamber to allow an exhaustgas to flow through the inner flame combustor; an igniter for ignitingthe mixed gaseous fuel injected toward the inside of the inner flamecombustor; and a flame sensor for sensing whether the flame is made onthe surface of the inner flame combustor or not.

The burner may further include at least one of swirlers disposed at aninlet of the combustion chamber to swirl the exhaust gas so as to flowthe exhaust gas into the inside of the inner flame combustor while theexhaust gas swirling.

The connecting pipe may be disposed in a tangential direction from thecross section of the combustion chamber in order to flow the exhaust gasinto the inner flame combustor disposed in the combustion chamber.

The inner flame burner may have a cyclone shape.

The burner may further include a gas-flow uniform unit disposed betweenthe mixed gas supplying unit and the mixed gas storing chamber in anannular shape that forms a concentric circle with the combustion chamberfor making the mixed gas to uniformly flow into the mixed gas storingchamber in a radial direction of the combustion chamber.

The burner may further include a flow-rate uniform unit for making aflow-rate of a mixed gas uniform in a length direction of the mixed gasby sustaining the pressure distribution of the mixed gas uniformly inthe length direction of the inner flame combustor.

The carburetor may include: a gasifying chamber for gasifying a liquidfuel; an atomizer for atomizing the liquid fuel into fine liquid dropsand supplying the atomized liquid fuel to the gasifying chamber; and aconvey air inflow line for forming a channel to flow an external airinto the gasifying chamber for conveying the gasified fuel into a mixedgas supplying unit.

The convey air inflow line may have a predetermined portion disposed topass the exhaust gas channel of the diesel engine for heating an externair flowing along the convey air inflow line through heat-exchangingwith the exhaust gas outputted from the diesel engine and flowing theheated air into the gasifying chamber.

The mixed gas supplying unit may include: a mixing chamber for forming amixed gas by mixing an external air for burning and a gasified fuel; aburning air inflow line communicated with the mixing chamber for forminga channel for flowing an external air for burning into the mixingchamber; a fuel inflow line communicated with the mixing chamber and thegasifying chamber for forming a channel for flowing a gasified fuel intothe mixing chamber; a mixed gas inflow line communicated with the mixingchamber and the combustion chamber for forming a channel for flowing themixed gas from the mixing chamber into the mixed gas storing chamber.

An external air inflow passage formed in the burning air inflow line andthe mixing chamber may be formed in a ventury shape that has across-section gradually reduced along the flow of the external air forburning.

The burning air inflow line may have a predetermined portion disposed topass the exhaust gas channel of the diesel engine for heating anexternal air flowing along the convey air inflow line throughheat-exchanging with the exhaust gas outputted from the diesel engineand flowing the heated air into the mixing chamber.

The burner may further include an electric control unit for electricallyfeedback-controlling: a temperature and a pressure of at least one spotin the combustion chamber; an amount of flowing external air forconveying into the gasifying chamber, a temperature and pressure insidethe gasifying chamber; a temperature, a pressure, and an amount offlowing an external air for burning into the mixed gas supplying unit;an amount of flowing a liquid fuel supplied from the fuel pump; atemperature and a pressure of an exhaust gas after passing through adiesel particulate filter; and operations of the combustor, the igniter,the flame sensor and the fuel pump.

The gasifying unit may include: an electric valve for controlling anamount of external air for conveying, which is supplied through theconvey air inflow line, in response to the electric control unit; and atemperature and pressure sensor for sensing a temperature and pressurein the gasifying chamber and providing the sensing signal to theelectric control unit.

The mixed gas supplying unit may include: an electric valve forcontrolling an amount of flowing an external air for burning, which issupplied through the burning air inflow line, in response to theelectric control unit; and a temperature and pressure sensor for sensinga temperature and pressure of the external air for burning and providingthe sensing signal to the electric control unit.

The burner may further include: a clean air supplying line communicatedwith an outside for supplying an external air into an ignite member ofthe igniter; and an electric valve for controlling an amount of flowingthe external air supplied from the clean air supplying line in responseto the electric control unit.

The burner may further include: a clean air supplying line communicatedwith an outside for supplying an external air to a flame sensing memberof the flame sensor; and an electric valve for controlling an amount offlowing the external air supplied from the clean air supplying line inresponse to the electric control unit.

The electric control unit may drive the burner when a difference ofpressures detected at a front and a rear of a diesel particulate filteris greater than a pre-determined threshold, and stops the burner whenthe difference is smaller than the pre-determined threshold.

An inner surface of the combustion chamber may be lined with at leastone of ceramic wool, creak wool or fire brick.

The porous material of the combustor may be one selected from the groupconsisting of mat type metal fiber, ceramic and foam metal.

The inner flame combustor may have one selected from the groupconsisting of a cylinder shape, a cone shape, a rectangle pipe shape,and combination thereof, which include a hollow hole defining theexhaust gas channel.

The burner may further include a heat resistant metal mash separatelydisposed inside the inner flame combustor for radiant heat-exchangingwith the inside surface of the inner flame combustor.

The inner flame combustor may further include a porous supporting memberfor holding the shape of the porous material by being connected to theouter surface of the porous material.

The igniter may be one of a spark plug for igniting the mixed gas bygenerating electrical sparks, and a grow plug for accumulating heat atthe one end.

Advantageous Effects

A burner for regenerating a diesel particulate filter according to thepresent invention has following advantages.

At first, the burner according to the present invention can instantlyignite and extinguish flames because the burner includes an inner flamecombustor that is formed of porous metal fiber having a plurality offine flame holes. After forming the flame on the inner flame combustor,the burner can stably sustain the flames in the flow of exhaust gas whenthe exhaust gas flows into a combustion chamber, when the engine is keptticking over, when the engine is driven at a constant speed. Also, theinner flame burner according to the present invention can sustain theflame stably while the exhaust gas outputted from the diesel engineflows into the combustion chamber, and when the amount of flowing theexhaust gas and the pressure thereof abruptly change due to the abruptvariation of the load of the diesel engine.

Since the burner according to the present invention includes the innerflame combustor having a comparatively larger surface by forming theinner flame combustor made of porous material in a cylinder shape, and arectangle pipe shape, the heat can be transferred quickly from theflames to the exhaust gas, and the constant temperature is uniformlysustained in the combustion chamber.

Furthermore, the burner according to the present invention swirls theexhaust gas to move soot particles in the exhaust gas toward the edgesof the flow of the exhaust gas and forms the flames along the edges toeffectively oxidize the soot particles so as to reduce the concentrationof the soot particles in the exhaust gas that flows into the filter.Therefore, the life time of the filter is lengthened because the lowconcentrated exhaust gas flows into the filter, and the amount of fuelwasted for forming flames is reduced because the burning interval of theburner is also lengthened.

In addition, the inside wall of the combustion chamber is lined withheat resistant material such as ceramic and firebrick to insulate and toaccumulate heat at the same time, and the insulating material can besustained to be clean because the soot particles on the insulatingmaterial are oxidized by the accumulated heat.

Moreover, the burner according to the present invention effectivelyregenerates a diesel particulate filter by stably sustaining the flames.Therefore, the burner can effectively prevent the environmentalpollution caused by the exhaust gas.

Finally, the burner according to the present invention can be used toregenerate a particulate filter in diesel engines which are equipped intrains, vessels and vehicles. The applicability of the burner accordingto the present invention is very wide as other purposes of the burner.It is very valuable in a view of the environmental population.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram a conventional diesel particulate filter;

FIG. 2 is a diagram illustrating a diesel particulate filter having aburner for regenerating the diesel particulate filter according to thefirst embodiment of the present invention;

FIG. 3 is a diagram illustrating a diesel particulate filter having aburner for regenerating the diesel particulate filter according to thesecond embodiment of the present invention; and

FIGS. 4 through 7 show a burner for regenerating a diesel particulatefilter according to the third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Other objects and aspects of the invention will become apparent from thefollowing description of the embodiments with reference to theaccompanying drawings, which is set forth hereinafter.

FIG. 2 is a diagram illustrating a diesel particulate filter having aburner for regenerating the diesel particulate filter according to thefirst embodiment of the present invention.

Referring to FIG. 2, the burner for regenerating the diesel particulatefilter according to the first embodiment includes one end connected toan exhaust gas channel through at least one of connecting pipes 131 andother end connected to a particulate filtering device such as a filter140 for collecting soot particles. The burner according to the firstembodiment includes an inner flame combustor 100 made of porous mat typemetal fiber for burning gasified fuel, a carburetor 120 for gasifyingfuel to supply the gasified fuel to the inner flame combustor 100, amixed gas supplying unit 110 for mixing the gasified fuel from thecarburetor 120 and an external air for burning and supplying the mixedgas to the inner flame combustor 100, a combustion chamber 130 where theinner flame combustor 100 is disposed and receives an exhaust gas from adiesel engine, and an electric control unit 160 for electricallycontrolling the burner.

The inner flame combustor 100 is made of porous material in order toinject the mixed gas, which is supplied into the combustion chamber 130,in a direction from the outside to the inside thereof. The inner flamecombustor 100 is disposed in the combustion chamber 130 so as to flowthe exhaust gas from the connected pipe 131 into the inside thereof. Theporous material of the inner flame combustor 100 may be mat type metalfiber, foam metal and ceramic which have high heat resistantcharacteristics. Herein, the inner flame combustor 100 may furtherinclude a porous supporting member 106 for holding the shape of theporous material by being coupled to the outside of the porous material.

Meanwhile, a heat resistant metal mash 107 may be disposed inside theinner flame combustor 100 to be separated from the inner side of theinner flame combustor 100. The heat resistant metal mash 107 mayextremely raise the temperature of the exhaust gas that flows around theheat resistant metal mash 107 through radiant heat-exchanging with theinside of the inner flame combustor 100.

The carburetor 120 includes a gasifying chamber 121 for gasifying aliquid fuel, an atomizer 122 for atomizing liquid fuel such as diesel,which is pumped from a fuel tank (not shown) by a fuel pump 128, intofine liquid drops and supplying the atomized fuel, a heat source 123 forsupplying heat for gasifying the fuel, a temperature and pressure sensor124 for sensing the temperature and pressure of the atomizer 121 andsupplying the sensed signal to the electric control unit 160, a conveyair inflow line 125 for forming a passage to flow an external air to thegasifying chamber 121 in order to partially mix the gasified fuel withthe air and to convey the gasified fuel, an electric valve 126 forelectrically controlling the amount of flowing the external air, whichis supplied through the convey air inflow line 125, and a liquid dropconvey line 127 for flowing the liquid drops of atomized fuel from theatomizer 122 to the gasifying chamber 121.

The mixed gas supplying unit 110 mixes the gasified fuel from thecarburetor 120 and the external air for burning, and supplying the mixedair to the inner flame combustor 100. the mixed gas supplying unit 100includes a mixing chamber 111 for forming the mixed gas by mixing anexternal air with the gasified fuel, a burning air inflow line 112communicated with the mixing chamber 111 for forming a passage forflowing an air into the mixing chamber 111, a fuel inflow line 113communicated with the mixing chamber 111 and the gasifying chamber 121for forming a passage to flow the mixed gas into the mixing chamber 11,and a mixed gas inflow line 114 communicated with the mixing chamber 111and the combustion chamber 130 for forming a passage to flow the mixedgas into the combustion chamber 130. Herein, the passages for flowingthe external air for burning to the mixing chamber 111 through theburning air inflow line 112 is formed in a ventury shape that has agradually reduced cross-section. By forming the passage in the venturyshape, the mixed gas formed at the gasifying chamber 121 of thecarburetor 120 smoothly moves to the mixing chamber 111 of the mixed gassupplying unit 110. Therefore, the mixed gas made of the fuel and theair is smoothly supplied to the inner flame combustor 100.

A gas-flow uniform unit 133 makes the mixed gas to flow from the mixedgas supplying unit 110 into a mixed gas storing chamber 134 uniformly ina radial direction of the combustion chamber. The gas-flow uniform unit133 has an annular shape that forms the concentric circle with the innersurface of the combustion chamber 130 and is made of porous materialsuch as honeycomb. The gas-flow uniform unit 133 makes the mixed gas toflow uniformly into the mixed gas storing chamber 134. Then, the mixedgas is injected through the surface of the inner flame combustor 100that is disposed in the combustion chamber and made of porous material.When the mixed gas is injected through the inner flame combustor 100,the igniter 101 ignites the mixed gas injected from the surface of theinner flame combustor 100 to the inside thereof through electricdischarging. Then, the flames are formed on the inner flame combustor100 toward the inside of the inner flame combustor 100.

The ignite performance of the igniter 101 may be degraded by pollutionsuch as soot particles. Therefore, a grow plug may be used as theigniter 101. The grow plug ignites the mixed gas by accumulating heat atthe one end thereof. If a spark plug, which ignites the mixed gas bygenerating the electrical sparks, is used as the igniter 101, theigniter 101 must be sustained as clean. In order to sustain the igniter101 to be clean, a clean air supplying line 104 may be further includedto supply clean external air to the igniter 101. Also, since the igniter101 must be stopped when the flames are formed on the inner flamecombustor 100, a flame sensor 103 is disposed. In order to sustain theflame sensor 103 or a flame sensing member of the flame sensor 103 to beclean, a clean air inflow line 104 may be further included for supplyingfresh air.

The combustion chamber 130, which provides a space for receiving theexhaust gas from the diesel engine, includes a fireproof thermalinsulator 132 for thermally insulating all walls that contact theexternal environment. In the combustion chamber 130, a temperature andpressure sensor 138 for sensing a temperature and pressure in thecombustion chamber 130 is disposed and a connecting pipe 131 isconnected as an exhaust gas passage. Also, the elements of the burnersuch as the inner flame combustor 100, the igniter 101, the flame sensor103 and the clean air inflow line 104 are disposed in the combustionchamber 130.

Meanwhile, electric valves 126, 115, 105 and 129 are disposed to controlthe amount of flowing an external air for conveying, the amount offlowing an external air for burning, the amount of flowing a clean air,and the amount of flowing the fuel in the fuel pump. The levels ofopening and closing the electric valves 126, 115, 105 and 129 arecontrolled by the electric control unit 160 through exchanging thesensing signals with the electric control unit 160. The electric controlunit 160 feedback controls the operations of the igniter 101, the powersupply 102, and the flame sensor 103, and the sensing and controloperations of the temperature and pressure sensor 138 in the carburetor120 in order to normally drive the elements.

Hereinafter, the operation of the burner according to the presentinvention will be described.

When a diesel engine is driven, an exhaust gas passes the inside of theinner flame combustor 100 disposed in the combustion chamber 130 alongthe connecting pipe 131 and is outputted through a discharging pipe 150.While the exhaust gas passes, the Soot particles and SOF included in theexhaust gas are trapped in a diesel particulate filter 140 which isdisposed between the combustion chamber 130 and the discharging pipe150. As the amount of soot particles trapped in the diesel particulatefilter 140 increases, the pressure loss of the diesel particulate filter140 gradually increases. The temperature and pressure sensor 138disposed at the front end of the diesel particulate filter 140, and thetemperature and pressure sensor 141 disposed at the rear end of thediesel particulate filter 140 continuously transfer the pressure andtemperature signals of the particulate filter 140 to the electriccontrol unit 160. When the pressure difference between the front and therear end of the particulate filter 140 becomes greater than apredetermined threshold value, the burner is driven as follows inresponse to an operation start signal from the electric control unit160.

When the fuel pump 121 is driven according to the operation start signalfrom the electric control unit 160, the atomizer 122 atomizes the liquidfuel and the atomized fuel flows into the gasifying chamber 121. Thegasifying chamber 121 gasifies the fuel using the gasifying heat source123. The gaseous fuel is mixed with the air injected from the convey airinflow line 125. Then, the gaseous fuel mixed with the air flows intothe mixing chamber 111 in the mixed gas supplying unit 110 through thefuel inflow line 113. Herein, the external air for burning flows intothe mixing chamber 111. As a result, the mixed gas is supplied to theinner flame combustor 100 quantitatively by storing the mixed gas in themixed gas storing chamber 123 through the gas-flow uniform unit 133.Then, the mixed gas is injected into the exhaust gas flowing inside theinner flame combustor 100. Herein, the power is supplied to the igniter101 from the high voltage power supply 102, and the igniter 101 ignitesthe mixed gas so as to form flames in a direction from the surface ofthe inner flame combustor 100 toward the inside of the combustionchamber.

After forming the flames on the inner flame combustor 100, the flamesensor 103 transmits a flame detecting signal to the electric controlunit 160, and the igniter 101 is stopped in response to a signaltransmitted from the electric control unit 160. Then, the flames arestably sustained on the inner flame combustor 100.

The flame formed on the inner flame combustor 100 oxidizes the sootparticles trapped in the diesel particulate filter 140 by increasing thetemperature of the exhaust gas flowing through the combustion chamber130 higher than the oxidization temperature of the soot particles. Thatis, the diesel particulate filter 140 is regenerated.

If the pressure difference between the front and the rear end of thediesel particulate filter 140 returns to an original state, the electriccontrol unit 160 stops the fuel pump 128. Accordingly, the carburetor120 also stops. According to the operations of the electric values 126,115, 105 and 129, the inflow of external air for conveying and burningalso stops so as to extinguish the flame on the inner flame combustor100. As described above, the electric control unit 160 controls theburner to ignite the flame, to sustain the flame stably and toextinguish the flame according to the pressure difference between thefront and the read end of the diesel particulate filter 140 that trapsthe soot particles. Therefore, the regeneration of the dieselparticulate filter 140 is stably performed even if the diesel engine isdriving.

Also, the electric control unit 160 automatically controls the amount offuel, the amount of flowing the air for conveying and burning to be theoptimal state according to the driving condition variation of the dieselengine. Therefore, the flames on the inner flame combustor 100 can bestably sustained without being extinguished although the drivingcondition of the diesel engine abruptly changes.

Meanwhile, the most of conventional burners for regenerating a dieselparticulate filter are a liquid fuel injection type burner that oftenunintentionally extinguishes the flames or cannot sustain the flamesstably when the load variation of the diesel engine abruptly changes.Therefore, the most of the conventional burners is driven only when thediesel engine is regularly driven, for example, when the engine is keptticking over, when the engine is driven at a constant speed, and whenthe engine stops. Therefore, the conventional burner cannot be used forregeneration practically.

However, in the present invention, since the inner flame combustor 100is made of porous material having a plurality of fine flame holes suchas metal fibers, a plurality of short flames are formed atallatonceness. Also, the heat on the inner flame combustor 100 preventsthe flames from being easily extinguished and quickly ignites flames allover the surface of the inner flame combustor 100. Since the flames onthe inner flame combustor 100 are formed along the edges of the exhaustgas flow, the flames can sufficiently heat the inner flame combustor 100although the driving condition of the diesel engine and the amount offlowing the exhaust gas abruptly change. Moreover, since the size offlame is very small, the variation thereof is also very small.Therefore, the flames on the inner flame combustor 100 are stablysustained.

When the exhaust gas flows into the inside of the inner flame combustor100 disposed in the combustion chamber 130 after forming the flame onthe inner flame combustor 100, the burner according to the firstembodiment can ignite, extinguish and stably sustain the flames in theflow of exhaust gas when the exhaust gas flows into a combustionchamber, when the engine is kept ticking over, when the engine is drivenat a constant speed. Also, the burner according to the first embodimentcan sustain the flame stably while the exhaust gas outputted from thediesel engine flows into the combustion chamber, and when the amount offlowing the exhaust gas and the pressure thereof abruptly change due tothe abrupt variation of the load of the diesel engine.

While the burner according to the present invention has been describedwith respect to the first embodiment, it will be apparent to thoseskilled in the art that various changes and modifications may be made.That is, the burner according to the present invention may includevarious embodiments that gasifies a liquid fuel, injects the gasifiedfuel through the inner flame combustor 100 which is made of porousmaterial and disposed along the edges of the combustion chamber wherethe exhaust gas flows into, and ignites the gasified fuel to form flameson the inner flame combustor 100 so as to transfer the heat from theedges of the exhaust gas to the center area by the flames. Herein, theporous material may be porous metal mat, metal fiber mat, porousceramic, foam metal and foam ceramic.

Also, an ultrasonic liquid fuel atomizer 122 may be disposed between thefuel pump 128 and the gasifying chamber 121 to improve the gasifyingperformance. Although the ultrasonic liquid fuel atomizer 122 is notincluded, the object of the present invention can be archived throughusing the liquid fuel carburetor. Furthermore, various units that gasifyliquid fuel although the heat source is not used to gasify the liquidfuel may be used as the carburetor in the present invention.

In the first embodiment of the present invention, the external air flewinto the gasifying chamber 121 and the mixing chamber 111 is describedas the normal temperature air. However, the burner according to thepresent invention may pre-heat the external air by guiding the externalair to pass through the exhaust gas outputted from the engine beforeflowing into the gasifying chamber 121 and the mixing chamber 111. Thatis, the external air may be heated by heat-exchanging with the exhaustgas while passing the exhaust gas.

In the first embodiment of the present invention, the inner flamecombustor 100 has a cylinder shape. However, the present invention isnot limited thereby. It is obvious to those skilled in the art that theinner flame combustor 100 may have any shapes that allows the exhaustgas to pass through the hollow hole of the inner flame combustor 100 tothe diesel particulate filter.

Furthermore, the inner flame combustor 100 according to the firstembodiment is formed of porous metal fiber in a mat shape. However, theinner flame combustor 100 may be formed of porous metal, foam metal,porous ceramic or other high heat resistant porous materials.Hereinafter, a burner for regenerating a diesel particulate filteraccording to the second embodiment of the present invention will bedescribed with reference to FIG. 3. Since the burner according to thesecond embodiment has the similar structure compared to the burneraccording to the first embodiment, the detailed descriptions ofidentical elements will be omitted.

The burner according to the first embodiment has a structure thatinstantly stores gasified fuel from the carburetor into the mixed gasstoring chamber 134 through the gas-flow uniform unit 133 as shown inFIG. 2. However, the burner according to the second embodiment, as shownin FIG. 3, additionally includes a flow-rate uniform unit 135 in themixed gas storing chamber 134.

When the mixed gas is injected from the mixed gas storing chamber 134 tothe inside of the inner flame combustor 100, the injecting speeds in thelength direction of the inner flame combustor 100 are generallydifferent at spots in the length direction of the inner flame combustor100.

That is, the injecting speeds become varied by the influence of thepressure distribution in the length direction of the mixed gas storingchamber because the distance between the inner flame combustor 100 andthe side wall of the combustion chamber 130 is constant. In the burneraccording to the second embodiment, the flow-rate uniform unit 135disposed in the mixed gas storing chamber 134 for eliminating theinfluence of the pressure distribution in the length direction.

Hereinafter, a burner for regenerating a diesel particulate filteraccording to the third embodiment of the present invention will bedescribed with reference to FIGS. 4 through 7. Since the burneraccording to the third embodiment has the similar structure compared tothe burners according to the first and the second embodiments, thedetailed descriptions of the identical elements will be omitted.

When the exhaust gas flows from the diesel engine into the combustionchamber, the burner according to the third embodiment swirls the exhaustgas in order to maximize the regeneration efficiency.

Since the flames formed on the inner flame combustor 100 are formedalong edges of the combustion chamber 130, which is the outside of theexhaust gas flow, the flames are not influenced by the exhaust gas flowvariation. The heat is transferred from the flames to the exhaust gasmainly through radiant heat-exchanging with a convention current.Herein, the heat transfer mechanism between the flames and the exhaustgas significantly influences the level of increasing an exhaust gastemperature and the time of increasing the exhaust gas temperature. Ifthe flow of the exhaust gas is swirling, the heat transfer mechanism mayhave superior characteristics in the view of heat and material transfer.The centrifugal force made by swirling moves soot particles in theexhaust gas to the edges of the combustion chamber 130. Since the flamesare formed along the edges of the combustion chamber 130, the sootparticles in the exhaust gas are effectively oxidized. Finally, theconcentration of the soot particles in the exhaust gas becomes reducedwhen the exhaust gas enters the filter 140. Accordingly, the filter 140collects less amount of soot particles until the pressure difference ofthe filter 140 reaches at a predetermined threshold value. Therefore,the life time of the filter 140 becomes significantly lengthened, andthe performance thereof is also improved.

That is, the burning interval of the burner for the identical pressuredifference becomes extended so the life time of the filter 140 issignificantly lengthened. The amount of fuel used is also significantlyreduced in proportional to the lengthened burning interval.

Swirling the exhaust gas as described above can be achieved by modifyingthe configuration of the burner according to the present invention asfollows.

At first, as shown in FIG. 4, a burner for regenerating a dieselparticulate filter may be configured to have the above mentionedadvantages by disposing a swirler 136 at the inlet of the combustionchamber 130. The swirler 136 swirls the exhaust gas flew into thecombustion chamber 130. Then, the swirling exhaust gas flows into thecombustion chamber 130. The burner may additionally include theflow-rate uniform unit 135 for eliminating the influence of the pressuredistribution in the length direction, which is included in the burneraccording to the second embodiment as shown in FIG. 3, in the mixed gasstoring chamber 134 with the configuration that instantly stores thegasified fuel from the carburetor 120 in the mixed gas storing chamber134 through the gas-flow uniform unit 133 as shown in FIG. 5.

Secondly, as shown in FIG. 6, a burner for regenerating a dieselparticulate filter may be configured to have the above mentionedadvantages by disposing the connecting pipe 137 in a tangentialdirection for the cross section of the combustion chamber 130 in orderto flow the exhaust gas in the tangential direction of the combustionchamber 130. According to this configuration, the exhaust gas flows intothe combustion chamber 130 while the exhaust gas is swirling.Preferably, the burner may additionally include the flow-rate uniformunit 135 in the mixed gas storing chamber 134 for eliminating theinfluence of the pressure distribution in the length direction with thestructure that instantly stores the gasified fuel from the carburetor120 in the mixed gas storing chamber 134 through the gas-flow uniformunit 133 as shown in FIG. 2.

Thirdly, as shown in FIG. 7, a burner for regenerating a dieselparticulate filter may be configured to have the above mentionedadvantages by disposing the connecting pipe 137 in the tangentialdirection from the cross section of the combustion chamber 130 in orderto flow the exhaust gas in the tangential direction of the combustionchamber 130, and forming the inner flame combustor 100 in a cycloneshape that maximally uses the centrifugal force. In this case, anegative pressure is formed in the combustion chamber, and the negativepressure attenuates the pressure increment when the engine loads variesby the abrupt variation of driving conditions of the diesel engine.Therefore, the flames are further stably sustained although the engineload changes abruptly. Furthermore, it is preferable that the burner mayadditionally include the flow-rate uniform unit 135 having the identicalshape of the cyclone shape of the inner flame combustor 100 for removingthe influence of the pressure distribution in the length direction withthe structures that instantly stores the gasified fuel from thecarburetor 120 in the mixed gas storing chamber 134 through the gas-flowuniform unit 133.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A burner for regenerating a diesel engine particulate filter,comprising: a combustion chamber for receiving a exhaust gas from adiesel engine through at least one of connecting pipes connected to anexhaust gas channel of the diesel engine; a carburetor for gasifyingliquid fuel; a mixed gas supplying unit for mixing the gasified fuelfrom the carburetor with an external air for burning, and supplying themixed gaseous fuel to the combustion chamber; a mixed gas storingchamber disposed in the combustion chamber for receiving the mixedgaseous fuel from the mixed gas supplying unit and instantly storing thereceived mixed gaseous fuel; an inner flame combustor made of porousmaterial for injecting the mixed gaseous fuel supplied from the mixedgas storing chamber in a direction from the outside to the inside of theinner flame combustor, and disposed in the combustion chamber to allowan exhaust gas to flow through the inner flame combustor; an igniter forigniting the mixed gaseous fuel injected toward the inside of the innerflame combustor; and a flame sensor for sensing whether the flame ismade on the surface of the inner flame combustor or not.
 2. The burnerof claim 1, further comprising at least one of swirlers disposed at aninlet of the combustion chamber to swirl the exhaust gas so as to flowthe exhaust gas into the inside of the inner flame combustor while theexhaust gas swirling.
 3. The burner of claim 1, wherein the connectingpipe is disposed in a tangential direction from the cross section of thecombustion chamber in order to flow the exhaust gas into the inner flamecombustor disposed in the combustion chamber.
 4. The burner of claim 1wherein the inner flame burner has a cyclone shape.
 5. The burneraccording to claim 1, further comprising a gas-flow uniform unitdisposed between the mixed gas supplying unit and the mixed gas storingchamber in an annular shape that forms a concentric circle with thecombustion chamber for making the mixed gas to uniformly flow into themixed gas storing chamber in a radial direction of the combustionchamber.
 6. The burner of claim 5, further comprising a flow-rateuniform unit for making a flow-rate of a mixed gas uniform in a lengthdirection of the mixed gas by sustaining the pressure distribution ofthe mixed gas uniformly in the length direction of the inner flamecombustor.
 7. The burner of claim 1, wherein the carburetor includes: agasifying chamber for gasifying a liquid fuel; an atomizer for atomizingthe liquid fuel into fine liquid drops and supplying the atomized liquidfuel to the gasifying chamber; and a convey air inflow line for forminga channel to flow an external air into the gasifying chamber forconveying the gasified fuel into a mixed gas supplying unit.
 8. Theburner of claim 7, wherein the convey air inflow line has apredetermined portion disposed to pass the exhaust gas channel of thediesel engine for heating an external air flowing along the convey airinflow line through heat-exchanging with the exhaust gas outputted fromthe diesel engine and flowing the heated air into the gasifying chamber.9. The burner of claim 7, wherein the mixed gas supplying unit includes:a mixing chamber for forming a mixed gas by mixing an external air forburning and a gasified fuel; a burning air inflow line communicated withthe mixing chamber for forming a channel for flowing an external air forburning into the mixing chamber; a fuel inflow line communicated withthe mixing chamber and the gasifying chamber for forming a channel forflowing a gasified fuel into the mixing chamber; a mixed gas inflow linecommunicated with the mixing chamber and the mixed gas storing chamberfor forming a channel for flowing the mixed gas from the mixing chamberinto the mixed gas storing chamber.
 10. The burner of claim 9, whereinan external air inflow passage formed in the burning air inflow line andthe mixing chamber are formed in a ventury shape that has across-section gradually reduced along the flow of the external air forburning.
 11. The burner of claim 9, wherein the burning air inflow linehas a predetermined portion disposed to pass the exhaust gas channel ofthe diesel engine for heating an external air flowing along the conveyair inflow line through heat-exchanging with the exhaust gas outputtedfrom the diesel engine and flowing the heated air into the mixingchamber.
 12. The burner of claim 7, further comprising an electriccontrol unit for electrically feedback-controlling: a temperature and apressure of at least one spot in the combustion chamber; an amount offlowing external air for conveying into the gasifying chamber, atemperature and pressure inside the gasifying chamber; a temperature, apressure, and an amount of flowing an external air for burning into themixed gas supplying unit; an amount of flowing a liquid fuel suppliedfrom the fuel pump; a temperature and a pressure of an exhaust gas afterpassing through a diesel particulate filter; and operations of thecombustor, the igniter, the flame sensor and the fuel pump.
 13. Theburner of claim 12, wherein the gasifying unit includes: an electricvalve for controlling an amount of external air for conveying, which issupplied through the convey air inflow line, in response to the electriccontrol unit; and a temperature and pressure sensor for sensing atemperature and pressure in the gasifying chamber and providing thesensing signal to the electric control unit.
 14. The burner of claim 12,wherein the mixed gas supplying unit includes: an electric valve forcontrolling an amount of flowing an external air for burning, which issupplied through the burning air inflow line, in response to theelectric control unit; and a temperature and pressure sensor for sensinga temperature and pressure of the external air for burning and providingthe sensing signal to the electric control unit.
 15. The burner of claim12, further comprising: a clean air supplying line communicated with anoutside for supplying an external air into an ignite member of theigniter; and an electric valve for controlling an amount of flowing theexternal air supplied from the clean air supplying line in response tothe electric control unit.
 16. The burner of claim 12, furthercomprising: a clean air supplying line communicated with an outside forsupplying an external air to a flame sensing member of the flame sensor;and an electric valve for controlling an amount of flowing the externalair supplied from the clean air supplying line in response to theelectric control unit.
 17. The burner of claim 12, wherein the electriccontrol unit drives the burner when a difference of pressures detectedat a front and a rear of a diesel particulate filter is greater than apredetermined threshold, and stops the burner when the difference issmaller than the predetermined threshold.
 18. The burner of claim 1,wherein an inner surface of the combustion chamber is lined with atleast one of ceramic wool, creak wool or fire brick.
 19. The burner ofclaim 1, wherein the porous material of the combustor is one selectedfrom the group consisting of mat type metal fiber, ceramic and foammetal.
 20. The burner of claim 19, wherein the inner flame combustor hasone selected from the group consisting of a cylinder shape, a coneshape, a rectangle pipe shape, and combination thereof, which include ahollow hole defining the exhaust gas channel.
 21. The burner of claim 1,further comprising a heat resistant metal mash separately disposedinside the inner flame combustor for radiant heat-exchanging with theinside surface of the inner flame combustor.
 22. The burner of claim 1,wherein the inner flame combustor further includes a porous supportingmember for holding the shape of the porous material by being connectedto the outer surface of the porous material.
 23. The burner of claim 1,wherein the igniter is one of a spark plug for igniting the mixed gas bygenerating electrical sparks, and a grow plug for accumulating heat atthe one end.